Titanium-aluminium alloy applied to golf club head

ABSTRACT

A titanium-aluminum alloy applied to a golf club head includes 88 wt % to 92 wt % titanium (Ti) and 7.5 wt % to 10 wt % aluminum (Al), and an elongation of the titanium-aluminum alloy is from 8% to 16%. Minor elements such as niobium (Nb), vanadium (V), molybdenum (Mo), chromium (Cr), iron (Fe), silicon (Si), oxygen (O), and nitrogen (N) may be selectively added into the titanium-aluminum alloy, so as to form a high extensibility material with a tensile strength from 650 Mpa to 950 Mpa, which can be applied to a main body. A golf club head combining a high-stiffness hitting surface, which is made of 6Al-4V—Ti titanium alloy or β alloy, can achieve a golf club head product with good hitting sense, desirable damping capability, expected golf-controlling capability, and a customized feature of an adjustable angle at a club portion.

This application claims the benefit of Taiwan Patent Application No. 097101708, filed on Jan. 16, 2008, which is hereby incorporated by reference for all purposes as if fully set forth herein.

BACKGROUND OF THE INVENTION

1. Field of Invention

The present invention relates to a high extensibility material applied to a golf club head, and more particularly to a high extensibility material for a golf club head by formulating titanium (Ti) and aluminum (Al) at different weight ratios and adding minor elements, such as niobium (Nb), vanadium (V), molybdenum (Mo), chromium (Cr), iron (Fe), silicon (Si), oxygen (O), and/or nitrogen (N).

2. Related Art

Recently, the alloy technique developed to be applied to a golf club head is mainly titanium alloy material. US 2006/0045789 for example, a conventional titanium alloy 6Al-4V—Ti (i.e., the weight ratios of aluminum and vanadium are indicated, and the remaining is titanium) is disclosed, which includes 5.5 wt % to 6.75 wt % Al, 3.5 wt % to 4.5 wt % V, ≦0.3 wt % Fe, and ≦0.2 wt % O, and the conventional titanium alloy has a density of 4.43±0.3 g/cm³. As compared with the club head in earlier stage fabricated by stainless steel, the golf club head made of the 6Al-4V—Ti titanium alloy has higher elastic deformation force, the same strength, and lower density, and thus, under a precondition of without increasing the weight of the golf club head, the volume of the golf club head is increased, such that the area for the better hitting point is relatively enlarged, thereby improving the success ratio when hitting the golf ball. In addition, due to the elastic deformation force higher than that of the stainless steel, it can provide larger elastic deformation capability when hitting the ball, can generate larger elastic deformation-elongation rate, and can relatively reduce spherical compression deformation resulted when the golf ball hits the hitting plate, thereby reducing the hitting stress absorbed by damping, preventing the energy loss of the hitting stress, and further increasing the hitting distance.

However, till now, under the large-size volume and diversified customized requirements for the golf club head, it is necessary to develop a material with a low density and a high elongation, but still maintaining the original mechanical strength, thereby improving the design margin.

SUMMARY OF THE INVENTION

In view of the above requirements, the present invention is directed to a titanium-aluminum alloy with high plasticity and high extensibility, for adjusting an elastic deformation capability of the golf club head. The present invention is further directed to a titanium-aluminum alloy with high extensibility, in which trace amount of modifying elements may be added to fine modify the titanium-aluminum alloy. In order to solve the above problems, the present invention provides a titanium-aluminum alloy, which includes 88 wt % to 92 wt % titanium (Ti) and 7.5 wt % to 10 wt % aluminum (Al), and has an elongation falling within a scope from 8% to 16%.

The titanium-aluminum alloy is formed by casting, forging, or mechanically processing a titanium alloy with a density ≦4.40 g/cm³ and a tensile strength from 680 Mpa to 950 Mpa.

The present invention further provides a titanium-aluminum alloy, which includes: 88 wt % to 92 wt % Ti, 7.5 wt % to 10 wt % Al, ≦2 wt % niobium (Nb), ≦2 wt % vanadium (V), ≦2 wt % molybdenum (Mo), ≦2 wt % chromium (Cr), ≦1 wt % iron (Fe), ≦1 wt % silicon (Si), ≦0.3 wt % oxygen (O), and ≦0.05 wt % nitrogen (N), and has an elongation falling within a scope from 8% to 16% and a density ≧4.40 g/cm³.

In the titanium-aluminum alloy of the present invention, the content of Ti and Al is higher than that of 6Al-4V—Ti in the conventional art, and the increasing of the content of Al has a significant effect on improving the normal temperature and high temperature strength, reducing the specific gravity, and increasing the elastic modulus of the alloy. Nb, V, Mo, Cr, and Fe are β stable elements, and as compared with 6Al-4V—Ti, the adding amount of V is greatly reduced, thereby reducing the manufacturing cost of the titanium-aluminum alloy. Furthermore, the titanium-aluminum alloy of the present invention has desirable hot molding capability, so it can be easily manufactured through mass production in factory, and the density thereof is lower than the alloy of the same kind, which is helpful for following the large-size trend of the golf club head, thereby improving the design margin.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description given herein below for illustration only, which thus is not limitative of the present invention, and wherein:

FIG. 1 is a phase diagram of a titanium-aluminum alloy applied to a golf club head at a magnification of 50× according to an embodiment of the present invention;

FIG. 2 is a phase diagram of the titanium-aluminum alloy applied to a golf club head at a magnification of 100× according to an embodiment of the present invention; and

FIG. 3 is a phase diagram of the titanium-aluminum alloy applied to a golf club head at a magnification of 200× according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is illustrated below through preferred embodiments with reference to the drawings.

Referring to FIGS. 1, 2, and 3, according to a first embodiment of the present invention, the titanium-aluminum alloy includes: 88 wt % to 92 wt % Ti, 7.5 wt % to 10 wt % Al, and has an elongation falling within a scope from 8% to 16% and a density ≦4.40 g/cm³.

In the present invention, the properties of the titanium-aluminum alloy may be modified by adding trace amount of modifying elements, which may be, for example, selected from a group consisting of Nb, V, Cr, Mo, Fe, Si, O, and N elements. For example, the strength of the alloy may be enhanced by adding trace amount of Nb, without reducing the elongation property. The flowability and assistant degas effect during casting may be improved by relatively reducing the adding amount of V, without affecting the original mechanical property of the alloy. The uniformly-distributed carbide may be precipitated from the alloy by adding trace amount of Mo, so as to improve the heat resistance, to reduce the hot-crack phenomenon for welding of the alloy, and to increase the hardening capability and high-temperature strength of the alloy. The antirust and corrosion resistance of the alloy may be improved by adding suitable amount of Cr, so as to improve the service life of the golf club head. The material may have a desirable plasticity by adding trace amount of Fe, which is helpful for being processed. The flowability of the melted metal is improved by adding trace amount of Si. The modifying elements selected to be added into the present invention include ≦2 wt % Nb, ≦2 wt % V, ≦2 wt % Mo, ≦2 wt % Cr, ≦1 wt % Fe, ≦1 wt % Si, ≦0.3 wt % O, and ≦0.05 wt % N. The titanium-aluminum has an elongation falling within a scope from 8% to 16% and a density ≧4.40 g/cm³.

The characteristics of the titanium-aluminum alloy in the first to fourth embodiments of the present invention are compared with that of the conventional titanium alloy 6Al-4V—Ti as shown in Table 1 below:

TABLE 1 Tensile 0.2% Yield Strength Strength Elongation Hardness Material (Mpa) (MPa) (%) (HRC) Conventional 830-900 760-830 3-5 30-35 6Al—4V—Ti 8Al—Ti in the First 685-705 640-660  8-16 25-28 Embodiment of the Present Invention 8Al—2V—Ti in the 818-827 775-780 11.6 26-29 Second Embodiment of the Present Invention 7.5Al—2V—Ti in the 816-825 766-770 10.2 27-29 Third Embodiment of the Present Invention 7Al—2V—Ti in the 815-822 750-760  8.5 28-30 Fourth Embodiment of the Present Invention

As compared with the conventional 6Al-4V—Ti alloy, the titanium-aluminum alloy of the present invention can reduce the alloy density and increase the ductility by increasing the content of Al and reducing the content of V, thereby obtaining excellent elongation plasticity, and maintaining the low density.

A comparison table of the element composition of the titanium-aluminum alloy in the embodiment of the present invention with that of the conventional titanium alloy is as shown in Table 2 below:

TABLE 2 8Al—Ti in the Embodiment Element (wt %) Conventional 6Al—4V—Ti of the Present Invention Al 5.5-6.75 7.9-8.3 V 3.5-4.5  0.001 C 0.1↓ 0.010-0.012 N  0.05↓ 0.005-0.01  O 0.2↓ 0.09-0.11 Fe 0.3↓  0.06-0.007 Si 0.1↓ 0.01-0.03

The alloy material of the embodiment takes the titanium-aluminum alloy as the main alloy, which is formed by casting, forging, or mechanically processing a titanium alloy, and has an elongation from 8% to 16% (over 8%) and a tensile strength from 680 Mpa to 950 Mpa (above 680 Mpa).

The titanium-aluminum alloy of the present invention has higher elongation capability, which is suitable for forming the main body of the golf club head. Furthermore, other material with desirable rigidness may be used for forming the hitting surface. The material composition may be titanium alloy 6Al-4V—Ti and β titanium alloy etc., and the alloy may be formed through casting, forging, or mechanical processing. In the present invention, the material of the main body with high elongation capability combined with the hitting plate with high strength can be used for achieving the golf club head product with good hitting sense (desirable damping capability), expected golf-controlling capability and a customized feature of an adjustable angle at a club portion, together with the internal structural designs of the main body, weighting structure, and rib design. A comparison table of the processing performance of the 8Al—Ti of the present invention with that of the conventional 6Al-4V—Ti is as shown in Table 3.

TABLE 3 Processing 8Al—Ti in the Embodiment of the Performance Conventional 6Al—4V—Ti Present Invention Cool adjust angle Material is relatively brittle, and Material is relatively soft and cracks occur on the club portion flexible, and no cracks occur on when the angle is adjusted to 1.5 the club portion when the angle degrees. is adjusted to 3.5 degrees. Average 1.5 g 0.9 g Processing Amount for Each Club Head Average Grinding  12 g 9.3 g Amount for Each Club Head

In addition, in the present invention, the main body of the golf club head is made of 8Al—Ti in the embodiment, and meanwhile, the titanium alloy with a high strength, SP700, is welded thereon as the hitting surface. Through a cannon shot test with a cannon shot dedicated golf ball (at a specification of 90) for 3000 times at a speed of 55.8 m/s, the hitting plate and the main body of the club head are not broken or have any cracks through eye observation and crack detection test.

To sum up, the titanium-aluminum alloy provided in the present invention has the features of industrial utilization, novelty, and inventiveness, so as to meet the requirements of an invention patent. The present invention is not restricted to the particular details described in the preferred embodiments. Indeed, those skilled in the art having the benefit of this disclosure will appreciate that many other variations from the foregoing description and drawings may be made within the scope of the present invention. 

1. A titanium-aluminum alloy applied to a golf club head, comprising: 88 wt % to 92 wt % titanium (Ti) and 7.5 wt % to 10 wt % aluminum (Al), wherein the titanium-aluminum alloy has an elongation falling within a scope from 8% to 16%.
 2. The titanium-aluminum alloy applied to a golf club head as claimed in claim 1, wherein the titanium-aluminum alloy further comprises a modifying element selected from a group consisting of niobium (Nb), vanadium (V), molybdenum (Mo), chromium (Cr), iron (Fe), silicon (Si), oxygen (O), and nitrogen (N).
 3. The titanium-aluminum alloy applied to a golf club head as claimed in claim 2, wherein the modifying element comprises lower than 2% of Nb.
 4. The titanium-aluminum alloy applied to a golf club head as claimed in claim 2, wherein the modifying element comprises lower than 2% of V.
 5. The titanium-aluminum alloy applied to a golf club head as claimed in claim 2, wherein the modifying element comprises lower than 2% of Mo.
 6. The titanium-aluminum alloy applied to a golf club head as claimed in claim 2, wherein the modifying element comprises lower than 1% of Fe.
 7. The titanium-aluminum alloy applied to a golf club head as claimed in claim 2, wherein the modifying element comprises lower than 1% of Si.
 8. The titanium-aluminum alloy applied to a golf club head as claimed in claim 2, wherein the modifying element comprises lower than 0.3% of O.
 9. The titanium-aluminum alloy applied to a golf club head as claimed in claim 2, wherein the modifying element comprises lower than 0.05% of N.
 10. A titanium-aluminum alloy applied to a golf club head, comprising: 88 wt % to 92 wt % titanium (Ti), 7.5 wt % to 10 wt % aluminum (Al), ≦2 wt % niobium (Nb), ≦2 wt % vanadium (V), ≦2 wt % molybdenum (Mo), ≦2 wt % chromium (Cr), ≦1 wt % iron (Fe), ≦1 wt % silicon (Si), ≦0.3 wt % oxygen (O), and ≦0.05 wt % nitrogen (N), wherein the titanium-aluminum alloy has an elongation falling within a scope from 8% to 16%. 